In the LTE system, a handover control that maintains the communication state of a terminal that is communicating when it is moving between cells of base stations has been contemplated and defined in specifications [TS36.300 v.8.30].
However, in this control system, since the network side initiatively starts the handover control, the communication state of the terminal may not be reflected in real time. Thus, to assure the real time reflection of the communication state of the terminal, it is contemplated that the frequency of measurement should be increased. Moreover, in the LTE system, in consideration of the case in which a handover to a destination cell (base station) that is designated by the network side fails, a method that provides a plurality of cells as handover destination candidates has been proposed. In this proposed method, if a handover fails, by performing a reconnection process for a cell provided as a handover destination candidate, the communication state of the terminal can be maintained.
On the other hand, JP2007-6089A discloses a technique that causes a terminal to initiatively to be handed over based on received radio wave states of access points of a plurality of base stations.
Moreover, JP2007-13463A discloses a technique in which a superior station determines a handover process based on measurement information received from the terminal and the station notifies the terminal of the command message so as to execute hand over.